21425020 has 24 divisors (see below), whose sum is σ = 45126144. Its totient is φ = 8544576.

The previous prime is 21425009. The next prime is 21425021. The reversal of 21425020 is 2052412.

It is a junction number, because it is equal to n+sod(n) for n = 21424985 and 21425003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21425021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6262 + ... + 9058.

It is an arithmetic number, because the mean of its divisors is an integer number (1880256).

Almost surely, 2^21425020 is an apocalyptic number.

21425020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21425020 is an abundant number, since it is smaller than the sum of its proper divisors (23701124).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21425020 is a wasteful number, since it uses less digits than its factorization.

21425020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3189 (or 3187 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 21425020 is about 4628.7168848397. The cubic root of 21425020 is about 277.7412667864.

Adding to 21425020 its reverse (2052412), we get a palindrome (23477432).

The spelling of 21425020 in words is "twenty-one million, four hundred twenty-five thousand, twenty".